Lamp mounting structure

ABSTRACT

Disclosed is a mounting structure for a lamp comprising a lamp having a funnel, a frame attached to a front end of the funnel and a connecting bolt provided at a rear portion of the funnel a lamp holder, which is adapted to hold the lamp therein while maintaining a desired lateral gap at each of the frame of the lamp, have a bottom plate, a front plate and a pair of side plates. The lamp mounting structure maintains an alignment of the optical axis of the lamp while effectively preventing the lamp from being damaged due to a thermal expansion thereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lamp mounting structure. Moreparticularly to a lamp mounting structure capable of aligning theoptical axis of a lamp correctly while preventing a lamp from beingdamaged even when it is overheated. Thereby, the invention enhances thestability in the operation of the lamp and improve convenience inassociation with the use of the lamp. In particular, the presentinvention can be effectively employed to the cases in which thealignment of the optical axis of a lamp is important, such as the lampmounting structures of projectors.

2. Background of the Related Art

Generally, a display device using a projection system includes aprojector for projecting the light retaining an image signal, and ascreen for reflecting the light projected from the projector, therebydisplaying an image. The projector mainly includes a lamp for performinga light emitting function, a plurality of dichroic mirrors forreflecting or transmitting the light (white light) emitted from the lampselectively, a liquid crystal panel for receiving the light beamsseparated from the light by the dichroic mirrors, thereby forming animage while controlling the amount of the light incident on each pixelthereof, and projection lens for projecting the image formed by theliquid crystal panel while enlarging the image.

The lamp is an essential component of the projector since it determinesthe basic performance of the projector such as controlling thebrightness and color of the image projected onto the screen. FIGS. 1 and2 illustrate an embodiment of a conventional lamp. Referring to FIGS. 1and 2, the lamp 10 includes a funnel 12 serving as a mirror, a frame 14attached to the front end of the funnel 12, an iron core 16 arranged atthe rear portion of the funnel 12, a neck 18 adapted to partiallysurround the iron core 16, and a connecting bolt 19 protruded from theiron core 16. Metal material such as iron could be used to make the ironcore 16. The iron core 16 is mounted on the neck 18 by a gypsum materialinterposed therebetween.

The brightness and the color of the image displayed by the projectorvary greatly, depending on the direction of the light emitted from thelamp 10. Accordingly, it is necessary to firmly maintain the mountedstate of the lamp 10. To this end, the lamp 10 is firmly and accuratelymounted by a lamp holder 20 in order to prevent the optical axis of thelamp 10 from being miss-aligned in lateral, vertical and logitudinadirections, the directions of X, Y, and Z axis in FIG. 1, respectively.

The lamp holder 20, which serves as a mounting structure of the lamp 10,has a bottom plate 201, a front plate 202, and a pair of side plates203. The guide plates 22 are placed at both sides of the front plate 202to fasten the right and the left sides of the frame 14 to the lampholder 20. Vertically-extending guide plates 22 are provided at bothsides of the rear surface of the front plate 202. The guide plates 22serves to the frame 14 of the lamp 10, thereby holding the lamp 10 inthe longitudinal, z-axid, and lateral, x-axis, directions. The lampholder 20 also has a strip-shaped holding plate 30 mounted between theside plates 203 to hold the lamp 10 in the vertical, y-axis, direction.Both ends of the holding plate 30 are fitted in slots 203, which areformed at the side plates 203, respectively.

In the conventional lamp mounting structure having the above mentionedconfiguration, movements of the lamp 10 in lateral, x-axis directionsare restricted by the guide plates of the lamp holder 20, and movementsof the lamp 10 in vertical, y-axis, directions are restricted by theholding plate 30. Also, movements of the lamp 10 in longitudinal,z-axis, directions are restricted by the front plate 202 of the lampholder 20 and stoppers that are provided at the lower end of the guideplates 22. Thus, the movements of the lamp 10 are restricted to preventthe optical axis of the lamp 10 from miss-alignments in any direction.

Meanwhile, heat generated as a result of a high temperature, forexample, about 300° C. or above, at the lamp 10 isdue to the operationsof the lamp 10. This heat serves to over-heat the lamp 10, therebycausing the funnel 12 and the frame 14 to expand. When the funnel 12 andframe 14 expand, an excessive pressure is applied to the funnel 12 bythe lamp holder 20. Since the lamp 10 is placed in between the guideplates 22 of the lamp holder 20, the expansion may result in a crack,either at the funnel 12 or the neck 18.

If the width L2, the defined space between the guide plates 22,increases in order to prevent the lamp 10 from being damaged due to athermal expansion as described above, then the lamp 10 may movelaterally resulting in a miss-alignment of the optical axis a normalstate. Also, there may be a degraded uniformity of the image displayedon the screen. In particular, the miss-alignment of the optical axiscauses the displayed image on the screen to undesirably exhibitundersirable excessive yellow color at the periphery thereof.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the abovementioned problems. An object of the invention is to provide a lampmounting structure for a projector which is capable of maintaining adesired alignment of the optical axis of a lamp included in theprojector while allowing the lamp to move freely to an certian extent.Thereby the invention will be able to prevent the lamp from beingcracked due to an expansion caused by an excessive heat, thus achievingan improved stability in the operation of the lamp.

In accordance with the present invention, the object is accomplished byproviding a mounting structure for a lamp comprising: a lamp having afunnel, a frame attached to a front end of the funnel, and a connectingbolt provided at a rear portion of the funnel; a lamp holder, which isadapted to hold the lamp therein while maintaining a desired lateral gapat each side of the frame of the lamp, has a bottom plate, a front plateand a pair of side plates; and a guide that elastically supports thelamp in position comprises hinges formed at the opposite ends of theguide and mounted on the bottom plate of the lamp holder in a mannerthat allows the hinges to rotate, an engagement member arranged at anintermediate portion of the guide and placed at an upper end of thefront plate of the lamp holder and a contact member that is formed atthe opposite sides of the engagement member and comes in contact withthe lamp.

The lamp mounting structure according to the present invention allowsthe lamp to be enlarged and shifted to a certain extent with thestructure of the lamp holder. Therefore, this structure prevents eitherthe funnel or the neck of the lamp from being cracked even when the lampis heated. Accordingly, it is possible to lengthen the life of theproduct to which the lamp mounting structure is employed. In addition,the lamp mounting structure elastically holds the lamp using thestructure of the tension guide. Accordingly, when the optical axis ofthe lamp is miss-aligned due to a shift of the lamp, this miss-alignmentis immediately corrected. Thus, there is an advantage in that animproved stability in the operation of the product, for example, aprojector, is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects, and other features and advantages of the presentinvention will become more apparent after a reading of the followingdetailed description when taken in conjunction with the drawings, inwhich:

FIG. 1 is an exploded perspective view illustrating a conventional lampmounting structure;

FIG. 2 is an assembled perspective view illustrating the conventionallamp mounting structure;

FIG. 3 is an exploded perspective view illustrating a lamp mountingstructure according to an embodiment of the present invention; and

FIG. 4 is an assembled perspective view illustrating a lamp mountingstructure according to the embodiment of the present invention

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Now, preferred embodiments of the present invention will be described inaccordance with FIGS. 3 and 4. In FIGS. 3 and 4, elements correspondingto those in FIGS. 1 and 2 are denoted by the same reference numerals.

In FIG. 3, a lamp mounting structure for a projector according to anembodiment of the present invention is illustrated. The lamp mountingstructure includes a lamp holder 20 for holding a lamp 10, and a returnmeans for elastically returning the lamp 10 to an original position. Byusing the return means, the optical axis of the lamp 10 is aligned inall directions, when the lamp 10 moves away from the original position.

As mentioned above, the lamp 10 includes a funnel 12, and a frame 14provided at the front end of the funnel 12. Basically, the lamp holder20 has a bottom plate 201, a front plate 202, and a pair of spaced sideplates 203. In accordance with the present invention, the distance L3between the side plates 203 of the lamp holder 20 is slightly longerthan the lateral length Lt of the frame 14 by about 1 mm. That is, thelamp holder 20 is structured to support the lamp 10 while maintaining adesired gap between the frame 14 and the side plate 203.

The return means comprises a tension guide 40 having a curved structureto surround the side and upper surfaces of the funnel 12. The tensionguide 40 is hingably mounted to the bottom plate 201 of the lamp holder20 at both ends thereof. The tension guide 40 also has an intermediateportion engaged with the front plate 202, and the funnel and framecontact portions that are arranged at the opposite sides of theintermediate portion and are adapted to come into contact with thefunnel 12 and frame 14 of the lamp 10. The tension guide 40 may be awire member, which is able to be bent to have a desired shape. Thistension guide 40 has material and structural characteristics capable ofexhibiting a desired elasticity.

The shape of the tension guide 40 will be described in detail. Thetension guide 40 has a wire-shaped guide body, hinges 40a respectivelyprovided at the opposite ends of the guide body and mounted hingably tofixed members 24 mounted on the bottom plate 201, a funnel contactportions 40 b extending from respective hinges 40 a and serving to comeinto contact with the funnel 12, a frame contact portions 40 c extendingfrom the respective funnel contact portions 40 b and serving to comeinto contact with the frame 14, and an engagement portion 40 d providedat the intermediate portion of the guide body and engaged withengagement grooves 20 a formed at the upper end of the front plate 202.

The tension guide 40 is mounted hingably to the bottom plate 201 usingits hinges 40 a mounted hingably to the fixed members 24. Once the lamp10 is arranged in position in the lamp holder 20, the tension guide 40is moved to engage its engagement portion 40 d with the engagementgrooves 20 a formed at the upper end of the front plate 202. Thus, thelamp 10 is firmly held in the lamp holder 20 by the tension guide 40.

Four contacts 41 are formed between the lamp 10 and the tension guide 40to define the position of the lamp 10 in the lamp holder 20.

The principle of positioning the lamp 10 by the tension guide 40 will bedescribed hereinafter.

As shown in FIG. 4, contacts 41, a first contact 41 a and a secondcontact 41 b, are formed at each side of the lamp 10 between the funnel12 and an associated funnel contact portions 40 b. In FIG. 4, thetension guide 40 applies a force to the lamp 10 in leftward, rearward,and downward directions at the first contact 41 a, while applying aforce to the lamp 10 in left, rearward, and upward directions at thesecond contact 41 b. Although not shown, the force of the tension guide40 is applied to the left side of the lamp 10 in symmetrical directionsto the force applied to the right side of the lamp 10.

The forces applied to the lamp 10 by the tension guide 40 are symmetricin a vertical, y-axis, direction and a lateral, x-axis, direction, sothat they are offset by each other. Also, the force of the tension guide40 in a longitudinal, z-axis, direction is applied to the front plate202. Thus, the lamp 10 is firmly held in the lamp holder 20 in a statein which the forces applied to the lamp 10 by the tension guide 40 arebalanced. When the force's balance is lost due to a positional shift ofthe lamp 10, a return force from the tension guide 40 is applied to thelamp at the contacts 41. With the return force, the lamp 10 isimmediately moved to its original position where the optical axis of thelamp 10 is aligned in all directions. Thus, a desired alignment of theoptical axis of the lamp 10 can be easily achieved.

The tension guide 40 may be structured to form additional contacts 41 cand 41 d where the frame contact portions 40 c come into contact withthe upper surface of the frame 14. In this case, a force from thetension guide 40 is applied downward to the frame 14 against the bottomplate 201. With this force, the lamp 10 can be held more firmly in thevertical direction.

In accordance with the lamp mounting structure having the abovementioned configuration, the lamp 10 is laterally movable to some extentin which the frame 14 of the lamp 10 is in contact with the front plate202 of the lamp holder 20. Accordingly, even when the funnel 12 andframe 14 are deformed to have an enlarged size or are shifted due to theheat generation during the operation of the lamp 10, such phenomenon isabsorbed by the tension guide 40 using the elasticity of the tensionguide 40. Accordingly, there will be no crack in either the funnel 12 orhte neck 18.

In particular, when the lamp 10 is shifted resulting in a miss-alignmentof the optical axis thereof, the tension guide 40 applies an elasticpressure to the lamp 10 in a direction opposite to the shift directionof the lamp 10. Also, its structure surrounds the left and right sidesurfaces and upper surface of the funnel 12. Accordingly, the positionof the lamp 10 is immediately corrected. Thus, the optical axis of thelamp 10 is maintained in lateral, vertical and longitudinal directions,X, Y, and Z-axis directions, respectively.

The lamp mounting structure according to the present invention allowsthe lamp to be enlarged and shifted to a some extent having thestructure including the lamp holder preventing the funnel or the neck ofa lamp from being cracked even when the lamp is heated. Accordingly, itis possible to lengthen the life of the product to which the lampmounting structure is applied. In addition, the lamp mounting structureholds the lamp elastically with the structure of the tension guide.Accordingly, when the optical axis of the lamp is mis-aligned due to ashift of the lamp, this mis-alignment is immediately corrected.Therefore, the improved stability in the operation of the product, forexample, a projector, is achieved.

Although the preferred embodiments of the invention have been disclosedfor illustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention as disclosed in theaccompanying claims.

What is claimed is:
 1. A mounting structure for a lamp comprising: alamp having a funnel, a frame attached to a front end of the funnel anda connecting bolt provided at a rear portion of the funnel; a lampholder, which is adapted to hold the lamp therein while maintaining adesired lateral gap at each side of the frame of the lamp, have a bottomplate, a front plate and a pair of side plates; and a guide thatelastically support the lamp in position comprises hinges formed at theopposite ends of the guide and mounted on the bottom plate of the lampholder in a manner that allows the hinges to rotate, an engagementmember arranged at an intermediate portion of the guide and placed at anupper end of the front plate of the lamp holder and a contact memberformed at the opposite sides of the engagement member and comes incontact with the lamp.
 2. The mounting structure according to claim 1,further comprising fixed members mounted on the bottom plate of the lampholder to allow the both ends of the guide to be attached with acapability to rotate.
 3. The mounting structure according to claim 1,wherein the contact members are arranged at opposite side portions ofthe funnel, respectively, so that each of them forms at least twocontact points with one of the side portions of the funnel and appliesan elastic force to the funnel via the contact points, therebymaintaining the lamp, in an elastic fashion, at a position where anoptical axis of the lamp is aligned in all directions.
 4. The mountingstructure according to claim 1, wherein the guide is a shaped metal wirehaving an elasticity.
 5. The mounting structure according to claim 1,wherein the guide further has additional contact members that extendfrom opposite ends of the engagement member and apply a force to theframe of the lamp in a downward direction, thereby causing the lamp tobe firmly held in a vertical direction.
 6. The mounting structureaccording to claim 1, further comprising: engagement grooves formed atthe upper end of the front plate of the lamp holder such that theengagement member of the guide may be placed in effective position.
 7. Astructure for mounting a lamp of a projector comprising: a lamp having afunnel, a frame attached to a front end of the funnel, and a connectingbolt provided at a rear portion of the funnel; a lamp holder thatadapted to hold the lamp includes a pair of side plates arranged atopposite sides of the frame of the lamp while maintaining a desiredlateral gap from an associated one of the opposite sides of the frame, afront plate being in contact with a front surface of the frame whileapplying a force to the lamp in a direction toward the lamp, and abottom plate being in contact with a bottom surface of the frame andsupporting the frame in a downward direction; and a tension guide thatadapted to elastically support the lamp in position includes the hingesprovided at opposite ends of the guide and hingably mounted to thebottom plate of the lamp holder, contact members having at least fourcontact points with the funnel where the tension guide come into contactwith the funnel of the lamp and engagement member, which is an extensionof the contact members, arranged at an intermediate portion of the guideand engaged with an upper end of the front plate of the lamp holder. 8.The structure according to claim 7, wherein the tension guide furtherhas additional contact members formed in between the engagement memberand the contact member, and come in contact with the frame such thatforce is applied to the frame of the lamp in a downward direction toprevent the lamp from moving vertically.
 9. The structure according toclaim 8, wherein the additional contact members are placed symmetricalwith each other.
 10. The structure according to claim 8, wherein thetension guide is a shaped metal wire having an elasticity.
 11. Thestructure according to claim 7, wherein the hinges and contact membersof the tension guide are symmetrically arranged so that the contactpoints are symmetrically arranged in vertical and lateral directionswith respect to the lamp.
 12. The structure according to claim 7,wherein the contact members of the tension guide are formed in acircular shape so that they are in contact with four corners of thelamp.
 13. A structure for mounting a lamp in a projector, comprising: alamp support adapted to support a frame of the lamp while maintaining adesired gap from the frame; and return means having at least fourcontact points to apply an elastic force to the lamp when the lamp movesout of position, thereby returning the lamp to an original positionwhere an optical axis of the lamp is aligned.
 14. The structureaccording to claim 13, wherein the return means comprises: a shapedmetal wire; a bottom plate included in the lamp support and adapted tosupport opposite ends of the metal wire; and a front plate of the lampsupport which allows the middle section of the metal wire to be placedon the upper front of the lamp support.
 15. The structure according toclaim 13, wherein the return means is mounted on the lower portion ofthe lamp support in a manner that allows the return means to rotate. 16.The structure according to claim 13, wherein the return means comprisesa shaped metal wire having a laterally symmetrical shape.
 17. Thestructure according to claim 13, wherein the contacts are symmetricallyarranged around the lamp.
 18. The structure according to claim 13,wherein the contacts are symmetrically arranged in a lateral directionwith respect to the lamp so that the lamp receives the same force inopposite lateral directions, respectively.
 19. The structure accordingto claim 13, wherein the contacts are symmetrically arranged in avertical direction with respect to the lamp so that the lamp receivesthe same force in opposite vertical directions, respectively.
 20. Astructure for mounting a lamp in a projector, comprising: a lamp supportadapted to support a frame to the lamp while maintaining a desired gapfrom the frame; and tension guide to apply an elastic force to the lampwhen the lamp moves out of position, thereby returning the lamp to anoriginal position where an optical axis of the lamp is aligned.
 21. Thestructure according to claim 20, wherein the tension guide has at leastfour contact points.
 22. The structure according to claim 20, whereinthe tension guide comprises: a shaped metal wire; a bottom plateincluded in the lamp support and adapted to support opposite ends of themetal wire; and a front plate of the lamp support which allows themiddle section of the metal wire to be placed on the upper front of thelamp support.
 23. The structure according to claim 20, wherein thetension guide is mounted on the lower portion of the lamp support in amanner that allows the return means to rotate.
 24. The structureaccording to claim 20, wherein the tension guide comprises a shapedmetal wire having a laterally symmetrical shape.
 25. The structureaccording to claim 21, wherein the contacts are symmetrically arrangedaround the lamp.
 26. The structure according to claim 21, wherein thecontacts are symmetrically arranged in a lateral direction with respectto the lamp so that the lamp receives the same force in opposite lateraldirections, respectively.
 27. The structure according to claim 21,wherein the contacts are symmetrically arranged in a vertical directionwith respect to the lamp so that the lamp receives the same force inopposite vertical directions, respectively.